This application claims priority of United Kingdom Patent Application No. 0021740.6 entitled xe2x80x9cDOWNHOLE CONTROL TOOL,xe2x80x9d filed on Sep. 05, 2000.
1. Field of the Invention
This invention relates to a downhole control tool.
2. Background of the Invention
In the oil and gas exploration and production industry, complex tools and devices will often be located in deep well bores. Control of such tools and devices from the surface may be affected by many different means, including control lines carrying electrical conductors, fiber optic cables or hydraulic fluid. The pressure of the fluid in the well, or of a fluid in a tubular in the well, may also be utilized. In many instances, a single well will contain a number of different tools and devices, all requiring separate control. Clearly, as the number of tools and devices increases, it becomes more difficult to provide separate control arrangements for the tools, for example it may become impractical to provide a separate hydraulic fluid control line for each tool or device.
It is among the objectives of embodiments of the present invention to facilitate control and operation of multiple downhole tools.
According to the present invention there is provided a downhole control tool comprising:
a first member defining a first profile;
a second member axially and rotatably movable relative to the first member and defining a second profile for selectively engaging the first profile; and
a third member axially movable relative to the first member and defining a third profile for selectively engaging the second profile,
the profiles being engaged and disengaged by axial reciprocal movement of the third member; and
the profiles being arranged such that on at least one of the second profile engaging the first profile and the second profile engaging the third profile, the second member is rotated relative to the first member.
Thus, the present invention provides an arrangement which converts a reciprocal movement into a rotary movement, which is useful in many applications, as will be described.
Preferably, the second member is a tool or device actuating member for selectively actuating a tool or device when the member is in a selected rotational or axial position. Typically, the member will actuate a tool or device only when in a predetermined axial and rotational position, the position having been attained by a predetermined number of reciprocal movements of the third member. Most preferably, the tool comprises at least one valve for selective actuation by the second member. The at least one valve may be a shuttle valve. The valve may be normally closed, and is actuated to the open position by the second member. The valve may control fluid access to a control line for selectively actuating a respective tool or device. A plurality of individually actuatable valves may be provided. Of course the tool of the invention may be provided in combination with a wide range of other tools or devices and for use in actuating other tools and devices, in addition to valves.
Preferably, the second member is axially biased towards the first member, that is the second profile is biased towards engagement with the first profile.
Preferably, the third member is axially biased away from the second member, that is the third profile is axially biased out of engagement with the second profile.
Preferably, the members are annular members, such that the tool may be incorporated in a tubular string, and allow fluid or other means of communication therethrough.
Preferably, the profiles are annular and continuous, such that the second member may be rotated indefinitely.
Preferably, rotation of the second member is induced both by engagement of the first and second profiles and by engagement of the second and third profiles.
Preferably, the profiles comprise teeth.
The second profile may be in two parts, one part for engaging the first profile and another part for engaging the third profile. However, it is preferred that the second profile is in one part, for selectively engaging both the first and the third profiles.
Preferably, the third member is fluid actuated. Most preferably, the member defines a piston, but may alternatively define some other flow restriction or profile. In other embodiments the member may be actuatable by other means.
Preferably, the second member is located co-axially within the first member. The members may define co-operating slots, splines or other profiles to permit relative axial movement therebetween.